Synthesis of a metal-free texaphyrin

[GRAPHICS] The synthesis of a metal-free form of texaphyrin, an aromatic porphyrin-lik e macrocycle, is described. Previously, texaphyrins could only be obtained reproducibly in the form of metal complexes. Using ferrocenium cation as th e oxidizing agent and starting with a reduced porphyrinogen-like nonaromati c form of texaphyrin, we isolated, in good yield, the metal-free oxidized t exaphyrin as its HPF6 salt. This product was characterized by X-ray diffrac tion analysis, UV-vis spectroscopy, and cyclic voltammetry.